Two recent builds for my personal collection.
JazzMutt with threaded saddle, original Fender style 'threaded' bridge.
Belle du Jour with a Badass II I bought used in 1982 for my first FenderBird. I drilled it for string thru and it's been on a bunch of my basses.
Both pickup sets are DiMarzios and there's very little difference in the sound they make. Sustain is never a problem for me, depends more on the age and type of strings, accuracy in cutting of nut and bridge slot depth, etc IMO.
As far as cleaning, both Naval Jelly and vinegar are acids, they eat rust. Either works well for cleaning up chrome if you're careful. Should be fairly easy to get that BA shining. A flat file will do the job on the bottom.